Device and method for determining a range of a battery characteristic curve

Abstract

A device for determining at least one range of a battery characteristic curve for a battery in a vehicle, having a measuring device for measuring battery parameters, and an analysis unit including a device for determining the current state of charge (SOC) of the battery from the measured battery parameters, a device for determining a shift value (VW) from the difference of a measured battery parameter and a standard value derived from a standard battery characteristic curve considering the determined state of charge (SOC), and a device for determining at least one range of a new battery characteristic curve by adding the shift value (VW) to the standard battery characteristic curve.

The invention claimed is: 
     
       1. A device configured to determine at least a portion of a battery characteristic curve for a battery in a vehicle, comprising:
 a measuring device configured to measure a battery parameter; and 
 an evaluation unit comprising:
 a first device configured to determine a current state of charge of the battery from the measured battery parameter; 
 a second device configured to determine a shift value from a difference between the measured battery parameter and a standard value obtained from a standard battery characteristic curve based at least in part on the determined state of charge; and 
 a third device configured to obtain at least one portion of a new battery characteristic curve by adding the shift value to the at least one portion of the standard battery characteristic curve, 
 wherein the new battery characteristic curve is used to ensure that one or more safety related loads are supplied with energy, 
 wherein the shift value is determined from the difference between the determined state of charge of the battery and a standard state of charge, wherein the difference is obtained from a standard battery characteristic curve with the same open circuit voltage. 
 
 
     
     
       2. The device as claimed in  claim 1 , wherein the measuring device comprises a fourth device configured to measure a voltage and a current of the battery and a time. 
     
     
       3. The device as claimed in  claim 2 ,
 wherein the evaluation unit comprises a fifth device configured to determine the shift value from the difference between a measured open circuit voltage of the battery and a standard open circuit voltage, 
 wherein the difference is obtained from a standard battery characteristic curve with the determined current state of charge. 
 
     
     
       4. The device as claimed in  claim 2 ,
 wherein the evaluation unit comprises a fifth device configured to determine the shift value from the difference between the determined state of charge of the battery and a standard state of charge. 
 
     
     
       5. The device as claimed in  claim 1 , wherein the device is integrated into an ASIC. 
     
     
       6. A battery monitoring device, comprising:
 a measuring device configured to measure a battery parameter; and 
 an evaluation unit comprising:
 a first device configured to determine a current state of charge of the battery from the measured battery parameter; 
 a second device configured to determine a shift value from a difference between the measured battery parameter and a standard value obtained from a standard battery characteristic curve based at least in part on the determined state of charge; and 
 a third device configured to obtain at least one portion of a new battery characteristic curve by adding the shift value to the at least one portion of the standard battery characteristic curve; 
 
 a battery terminal connected mechanically and electrically both to the battery and to the device; and 
 a measuring resistor mechanically and electrically connected to the battery terminal and to the device, 
 wherein the new battery characteristic curve is used to ensure that one or more safety related loads are supplied with energy, 
 wherein the shift value is determined from the difference between the determined state of charge of the battery and a standard state of charge, wherein the difference is obtained from a standard battery characteristic curve with the same open circuit voltage. 
 
     
     
       7. A method for determining at least one portion of a battery characteristic curve of a battery in a vehicle, comprising:
 determining a current state of charge of the battery from a measured battery parameter; 
 determining a shift value from a difference between the measured battery parameter and a standard value determined from a standard battery characteristic curve based at least in part on the determined state of charge; and 
 obtaining at least one portion of a new battery characteristic curve by adding the shift value to the standard battery characteristic curve, 
 ensuring that one or more safety related loads are supplied with energy using the new battery characteristic curve, 
 wherein the shift value is determined from the difference between the determined state of charge of the battery and a standard state of charge, wherein the difference is obtained from a standard battery characteristic curve with the same open circuit voltage. 
 
     
     
       8. The method as claimed in  claim 7 , wherein the shift value is determined from the difference between a measured open circuit voltage of the battery and a standard open circuit voltage, wherein the difference is obtained from a standard battery characteristic curve with the determined state of charge. 
     
     
       9. The method as claimed in  claim 7 , further comprising determining the current state of charge of the battery by a ratio of a discharged capacity to a maximum capacity of the battery. 
     
     
       10. The method as claimed in one of  claim 9 , further comprising determining the discharged capacity of the battery by integrating a measured current of the battery over time. 
     
     
       11. The method as claimed in one of  claim 10 , wherein a discharging current of the battery is measured during a starting process of the vehicle. 
     
     
       12. The method as claimed in one of  claim 11 , wherein the battery characteristic curve is obtained in a range of 30% to 90% of an SOC portion.